import java.time.DayOfWeek;
import java.time.LocalDate;
import java.time.temporal.TemporalAdjuster;
import java.time.temporal.TemporalAdjusters;
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;
import java.util.Stack;

public class Demo14 {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        // 注意 hasNext 和 hasNextLine 的区别
        long[] arr = new long[81];
        arr[0] = 0L;
        arr[1] = 1L;
        arr[2] = 1L;
        fib(arr);
        while (in.hasNextInt()) { // 注意 while 处理多个 case
            int from = in.nextInt();
            int to = in.nextInt();
            long ret = 0;
            for(int i = from;i<=to;i++){
                ret+=arr[i];
            }
            System.out.println(ret);


        }
    }

    private static void fib(long[] arr) {
        for(int i = 2;i<=80;i++){
            arr[i] = arr[i-1]+arr[i-2];
        }
    }









    /*public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        // 注意 hasNext 和 hasNextLine 的区别
        while (in.hasNext()) { // 注意 while 处理多个 case
            String str1 = in.next();
            String str2 = in.next();

            char[] st1 = str1.toCharArray();
            char[] st2 = str2.toCharArray();
            int len1 = st1.length, len2 = st2.length;

            int left = 0,right=0;
            int count = 0;
            while(left<len1){

                while (left<len1 && right<len2){
                    if (st1[left]==st2[right]){
                        left++;
                        right++;
                    }else{
                        if (st1[left] != st2[0]){
                            left++;
                        }
                        right = 0;
                    }

                }
                //上边的循环玩了，表示有一个子串了,或者没有子串，具体那种情况需要看right
                //right 为len2表示有一个子串，否则表示没有子串
                if (left <= len1 && right==len2){
                    count++;
                    right = 0;
                }



            }
            System.out.println(count);



        }
    }*/





/*    public static void main(String[] args) {
        Integer a = 100;
        Integer b = 100;
        System.out.println(a == b);        // 输出 true
        System.out.println(a.equals(b));   // 输出 true

        Integer c = 200;
        Integer d = 200;
        System.out.println(c == d);        // 输出 false
        System.out.println(c.equals(d));   // 输出 true


        String str = "1";
        String str1 = new String("1");
        System.out.println(str==str1);
        System.out.println(str.equals(str1));
    }*/






    /*public static int[] arr = new int[100001];
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        fib(100000);
        // 注意 hasNext 和 hasNextLine 的区别
        while (in.hasNextInt()) { // 注意 while 处理多个 cas
            int n = in.nextInt();
            System.out.println(arr[n]);

        }
    }

    private static void fib(int n) {
        int a = 1;
        int b = 1;
        int c = 2;

        int i = 1;
        arr[0] = 1;
        arr[1] = 1;
        while (n > 1) {
            i++;
            c = a + b;
            c = c % 1000000;
            a = a % 1000000;
            b = b % 1000000;
            a = b;
            b = c;
            n--;
            arr[i]=c;
        }

    }*/

/*    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        // 注意 hasNext 和 hasNextLine 的区别
        while (in.hasNextInt()) { // 注意 while 处理多个 case
            int n=in.nextInt();
            int ret = fib(n);
            System.out.println(ret);

        }
    }

    private static int fib(int n) {
        int a = 1;
        int b = 1;
        int c = 2;
        if (n<=1){
            return 1;
        }
        while (n>1){
            c = a + b;
            c = c%1000000;
            a = a%1000000;
            b = b%1000000;
            a = b;
            b = c;

            n--;
        }

        return c;
    }*/











/*
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        // 注意 hasNext 和 hasNextLine 的区别
        while (in.hasNextInt()) { // 注意 while 处理多个 case
            int year = in.nextInt();
            int month = in.nextInt();
            int day = in.nextInt();
            int year1 = in.nextInt();
            int month1 = in.nextInt();
            int day1 = in.nextInt();

            int[] arr = {0,31,28,31,30,31,30,31,31,30,31,30,31};
            //素数的月份   2 3 5 7 11
            List<Integer> su = new ArrayList();
            su.add(2);
            su.add(3);
            su.add(5);
            su.add(7);
            su.add(11);

            int sum = 0;
            if (year==year1){
                //判断是否是闰年
                if (isRun(year)){
                    arr[2]=29;
                }else{
                    arr[2]=28;
                }
                //同一年 同一月
                if(month==month1){
                    if (su.contains(month)){
                        sum+=(day1-day+1);
                    }else{
                        sum+=(day1-day+1)*2;
                    }
                }else{
                    //同一年  不同月
                    for(int m = month;m<month1;m++){
                        if (su.contains(m)){
                            sum+=arr[m];
                        }else{
                            sum+=arr[m]*2;
                        }
                    }

                    if (su.contains(month1)){
                        sum+=day1;
                    }else{
                        sum+=day1*2;
                    }
                }



            }else{
                //不同年
                for(int i = year;i<year1;i++){
                    //判断是否闰年
                    if (isRun(i)){
                        arr[2]=29;
                    }else{
                        arr[2]=28;
                    }

                    //遍历每个月
                    for(int m = 1;m<=12;m++){
                        if (su.contains(m)){
                            sum+=arr[m];
                        }else{
                            sum+=arr[m]*2;
                        }
                    }

                }
                //最后一年
                //判断是否闰年
                if (isRun(year1)){
                    arr[2]=29;
                }else{
                    arr[2]=28;
                }
                for(int m = 1;m<month1;m++){
                    if (su.contains(m)){
                        sum+=arr[m];
                    }else{
                        sum+=arr[m]*2;
                    }
                }
                //最后一个月的那几天
                if (su.contains(month1)){
                    sum+=day1;
                }else{
                    sum+=day1*2;
                }

            }

            System.out.println(sum);





        }
    }

    private static boolean isRun(int i) {
        if (i%400==0 && (i%4==0 && i%100!=0)){
            return true;
        }
        return false;
    }
*/









/*    private static List<Integer> ret;
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        // 注意 hasNext 和 hasNextLine 的区别
        while (in.hasNextInt()) { // 注意 while 处理多个 case
            ret = new ArrayList<>();
            int n = in.nextInt();
            int tmp = n;

            while (n%2==0){
                ret.add(2);
                n/=2;
            }
            for(int i=3;i*i<=n;i++){
                if (isSu(i)){
                    while (n%i==0){
                        ret.add(i);
                        n/=i;
                    }
                }
            }
            if (n>2){
                ret.add(n);
            }


            System.out.print(tmp+"=");
            for(int i = 0;i<ret.size()-1;i++){
                System.out.print(ret.get(i)+"*");
            }
            System.out.print(ret.get(ret.size()-1));

        }
    }

    private static boolean isSu(int n) {
        for(int i=2;i*i<=n;i++ ){
            if (n%i==0){
                return false;
            }
        }
        return true;

    }*/





   /* private static List<Integer> ret;
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        // 注意 hasNext 和 hasNextLine 的区别
        while (in.hasNextInt()) { // 注意 while 处理多个 case
            ret = new ArrayList<>();
            int n = in.nextInt();
            dfs(n);

            System.out.print(n+"=");
            for(int i = 0;i<ret.size()-1;i++){
                System.out.print(ret.get(i)+"*");
            }
            System.out.print(ret.get(ret.size()-1));

        }
    }

    private static void dfs(int n) {

        int flag = 0;
        for(int i = 2;i<n;i++){
            if (isSu(i)){
                if (n%i==0){
                    flag = 1;
                    dfs(i);
                    dfs(n/i);
                    break;
                }
            }
        }
        if (flag==0){
            ret.add(n);
        }




    }

    private static boolean isSu(int n) {
        for(int i=2;i*i<=n;i++ ){
            if (n%i==0){
                return false;
            }
        }
        return true;

    }*/








/*

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        // 注意 hasNext 和 hasNextLine 的区别
        while (in.hasNextInt()) { // 注意 while 处理多个 case
            int year = in.nextInt();
            System.out.println(year+"-01-01");

            LocalDate date = LocalDate.of(year,1,1);
            LocalDate ret = date.with(TemporalAdjusters.dayOfWeekInMonth(3, DayOfWeek.MONDAY));
            System.out.println(ret);

            date = LocalDate.of(year,2,1);
            ret = date.with(TemporalAdjusters.dayOfWeekInMonth(3, DayOfWeek.MONDAY));
            System.out.println(ret);

            date = LocalDate.of(year,5,1);
            ret = date.with(TemporalAdjusters.lastInMonth(DayOfWeek.MONDAY));
            System.out.println(ret);

            System.out.println(year+"-07-04");

            date = LocalDate.of(year,9,1);
            ret = date.with(TemporalAdjusters.dayOfWeekInMonth(1, DayOfWeek.MONDAY));
            System.out.println(ret);

            date = LocalDate.of(year,11,1);
            ret = date.with(TemporalAdjusters.dayOfWeekInMonth(4, DayOfWeek.THURSDAY));
            System.out.println(ret);

            System.out.println(year+"-12-25");

        }
    }
*/

  /*  public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int year = in.nextInt();
        for(int i = 1;i<=12;i++){
            LocalDate date = LocalDate.of(year,i,1);
            LocalDate ret = date.with(TemporalAdjusters.dayOfWeekInMonth(3, DayOfWeek.FRIDAY));
            System.out.println(ret);

        }



    }

*/



/*
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        // 注意 hasNext 和 hasNextLine 的区别
        while (in.hasNextInt()) { // 注意 while 处理多个 case
            int a = in.nextInt();
            List<Integer> ret = new ArrayList<>();
            for(int i = 2;i<a/2;i++){
                if (isSu(i)){
                    if (a%i==0){
                        ret.add(i);
                        ret.add(a/i);
                        a/=i;
                    }
                }
            }



        }
    }

    private static boolean isSu(int n) {
        for(int i = 2;i*i<n;i++){
            if (n%i==0){
                return false;
            }
        }
        return true;
    }
*/













 /*   public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        // 注意 hasNext 和 hasNextLine 的区别
        while (in.hasNextInt()) { // 注意 while 处理多个 case

            int year = in.nextInt();
            // 2000-1-3 是星期一
            int[] month = {0,31,28,31,30,31,30,31,31,30,31,30,31};
            int count = 0;
            for(int i = 2000;i<year;i++){
                if (isR(i)){
                    count+=366;
                }else{
                    count+=365;
                }
            }
            if (isR(year)){
                month[2] = 29;
            }
            //要知道year年的第一天是星期几
            int one = ((count%7)+6)%7;
            String[] ret = new String[8];
            ret[0] = year+"-"+"01"+"-"+"01";
            //马丁
            int[] xingqiyi = new int[55];
            int dijitian = 1;
            while (one!=1){
                one = (one+1)%7;
                dijitian++;
            }
            xingqiyi[0] = dijitian;
            int i = 1;
            while (dijitian<=366){
                dijitian+=7;
                xingqiyi[i] = dijitian;
            }

            //马丁







        }
    }

    private static boolean isR(int i) {
        if ((i%4==0 && i%100!=0) || i%400==0){
            return true;
        }
        return false;
    }*/


}
